Electric cable.



J. H. CUNTZ. ELECTRIC CABLE. APPLICATION FILED APR. 13, 1905.

1,1 1 9,246. Patented Dec. 1, 1914.

2 SHEETS-SHEET 1.

WITNESSES:

J. H. GUNTZ. ELECTRIC CABLE. APPLICATION FILED APR.13,1905.

Patented Dec. 1, 1914.

2 SHEETS-SHEET 2.

Fig.6.

INVMOR BY MM ATTORNEY WITNESSES:

ra rnn rfiormon.

JOHANN'ES H. CU'NZIZ, F HOBOKEN, NEW JERSEY.

ELECTRIC CABLE.

Specification of Letters Patent.

Patented Dec. 1, 1914.

Application filed April s. was. Serial No. 255,431,

To whom itmayconcern Be it known that I, Jonnxxns' H. CUNTZ,

acitizen of the'United States, and residentof Hoboken, in -the county ofHudson and State of NewJersey, (whose post-ofiicefaddress is Hoboken,New Jersey,) have invented certain. new and useful Improve now generallyunderstood as denoting eel, 'tain'phenomena.' 'The'cause of suchmodifications is the combined infl'uenceof the resistance, the capacityand the. inductance of theline. In ordinary) long. distance lines,

particularlyon submarine and underground cables, the capacity and theresistance are primarilyw instrumental in producmg attenuation,\\'hi,le,the capacity causes distortion also- On .suchlines the capacityis sub stantially "uniformly distributed along their. length. v I

Myinvention relates to the construction of'cables and to .methods forwhollyor in parttcounteracting the effects of the ca Imordertoapplymysystem of long .distance electric wave transmission my primeobject is to increase the inductance of the,

line sufliciently to substantially or partly,

as the case may demand, counteract the effects of. thedistributedcapacity of the line. as electric lines of this sort" may be used invarious ways, as submarine, underground or aerial, thecapacity whieh'itis necessary to counteract varies accordingly and between verywidelimits. In the case of subarine cablesthere is large capacity which,

t'erefore, demands a large amount of insuch cables is great.

ductance. particularly where the length of By my construction a cablecan be produced with van inductance as large as may be required for thegiven conditions, and what is more important, the amount can bepredetermined andthe diunensions of the elements of my cable soadzjusted as to secure the proper amountin a w y mwhani albsupp nd cqlml c ally hesc modifications are such as dis-,

practicable. I am aware that there have been suggestions ofconstructions intended to increase inductance in a' line, but whichinvariably do not show means whereby such inductance can be sufiicientlyincreased for my purpose; or suchcons tructions have involved defectswhich would prevent successful operation of the line; more than this, insuch suggestions it ha'svnot been shown how the exact amountof'inductance can be predetermined.

In myconstruction I carry my conductor in a helical path, whichincreases-the in" duc'tance of the lineto an extent that in some casesmay beisulficient'; and moreover I use a core of paramagnetic materialabout which the conductor is helically wound, which one ables me to verymaterially further increase the inductance. As I can determinewithproperties of theelements of my eonstruction .whichbeanu'pon,theresults, I can proportion the materialin and. the arrangement of theparts of my-c'ables to acconiplishthe desiredresults with certainty, andmoreover can so selectand arrange them as to prevent complications whichexisted in suggestions which have at times been made, or which mightexist except for theproper material and arrangement which I show andhereinafterinore specifically describe, and, particularly, when in upconstruction a magnetizable COleJSAlStl, thearrangement is such that themagnetization is so small as to avoid any deleterious eflects.

In the accompanying drawings, Figure I diagrammatically shows theembodiment of my improvement in along distance transmission. system.Figl 2 shows a portion of a cable, partly in section, embodying the essential elements of my invention, Fig. 2" being a section of the sameWith'jts sheathing, while 2* shows a section of the same withoutsheathing. Fig. 3 is a portion of a construction intended to securepermanency vin the relative arrangement of parts, while 3 shows thesamein section. Fig. 4 shows a section of cable modified in certain details.Fig. 5 shows a portion 'of cable in which more detail of core andarrangement of conductors is illustrated, while 5" shows the fame insection. 6 shows a portion of cable modified in form for mechanicalrequirements of manufacture. Figs. 7, 8 and 9 show portions of threeforms of cable with h rarts pr p for '75 exactness the var ouselectrical andmagnetic given conditions and differing only inarrangement, while Figs. 7, 8" and 9" show respectively the sections ofthese different arrangements.

In Fig. 1 A is an electrical conductor, B is a core, or support for theconductor, 6 is a source of electric energy, f is a key which, with 6,shows conventionally means of imparting electrical impulses to theconductor A, while 9 indicates aconnection to earth. h indicates aninstrument to receive electrical impulses, and indicates a connection toearth. C is insulation. The electricalimpulses or waves emanating from ef pass along the conductor A to the instrument h. In this drawing theconductor is shown. as broken away in the middle, to indicate length. 1

In Figs. 2 and 2 the conductor A with its small amount of insulation iswound helically around the core B and this is 'incased in insulation Cabout which is the sheathing D which can be used to take the strain towhich the cable may be subjected, while in other cases the constructionshown in Fig. 2 without sheathing may be usedand the strains, if thereare any, taken by the core.

In Figs. 3 and 3 the core B is so made as to present a helical groovewhichis followed by the conductor A, while A is flattened as may bedesirable in cases as hereinafter shown, and should the core be ofelectrically conducting material, A is insulated as shown. Thisconstruction might be used where the capacity of a line is relativelysmall and the desired inductance can be obtained simply from the'helicaldisposition of the conductor, and where it might be desirable to avoidthe use of a paramagnetic core.

In Fig. 4, the conductor in several strands A", properly insulated, islaid around the central portion of the stranded core B, so as to besubstantially flush with the outer' layer of the core 13". This wouldhave mechanical advantages in aiforcling'a more compact construction, inwhich also the outside strands of the core would cooperate to hold theconductor in its helical position; in addition to which I am herebyenabled to more completely fill the area inclosed by my hellicalconductor with paramagnetic matel'la In Figs. 5 and 5 the core B isshown more in detail, revealing the strands, the construction which Iwould generally use in the practical embodiment of my invention, whilemy conductor as here shown consists of a plurality of wires, eachindividually insulated for mechanical simplicity, although theinsulation between the conducting material and the core is primarilyimportant, and which I may accomplish by wrapping the bunch ofconductors within insulation in such a way that only the convolutions ofthe sets of conductors will be insulated from each other. In thisarrangement it will be seen that the conductors are wound in theopposite direction from the strands of the core, which under certain coditions will give me better electro-magnetic results. The conductor iswound in opposite directions from the strands of the core, so as tocross the latter more nearly at right angles, in view of which any eddycurrents which might possibly be induced in the core strands will bereduced to a minimum.

In the use of my invention for certain con ditions of line and also forpossible mechanical requirements in construction I. find that advantagesmay be obtained by using the arrangement as shown in Fig. 6. In this theconductor, or its several parts. is wound around the stranded corein thesame direction as the surface strands of the core and for a, certainlength'at the sam'e pitch. This will insure the conductor fitting thesurface of the core more closely, preventing among other thingsdisplacement, while portions of the conductor are then wound at a.decreased .pitch, this increasing the number of turns sufficiently togive the required inductance. In my construction of cable in all itsvarious forms where a core of paramagnetic material is used, said coreis of that material solely to increase the inductance of the line.

and is not intended to carry current.

In Figs. 7, 8 and 9 there is shown a practical form of cable designed tosatisfy the conditions of a concrete case. The only difference in thethree figures is the disposition of the conductor, except that in Figs.7 and 8 the strands of the core are simply indicated as parallel to itsaxis, whereas in Fig. 9 the strands are shown in the preferredarrangement. I have here assumed a submarine cable with capacity andresistance such as are encountered in actual practice, and I havecalculated the amount of inductance necessary to be given to such a linein order to permit the transmission of telephonic messages. cure theproper amount of inductance, the dimensions" and arrangement of core andconductor are substantially as shown. In the three illustrations thetotal area of section of conductor is the same. In Fig. 8 the conductoris flattened. This permits of a more compact, mechanical constructionand at the same time makes it a better conductor for rapidly alternatingcurrents, as it affords a larger surface for the same cross section. Itis true that this increased surface would also increase the capacity,but its mechanical arrangement ermits a greater thickness of insulationEn' a given outside diameter of cable, which greater thickness ofinsulation will reduce the capacity. In

Fig. 9 I divide my conductor in order to give I find then that in orderto se- I greater security against parting of the conductor, and also tosecure a more simple and commercially practicable method of manufacture.In this the conductor consists of a plurality of wires, each insulatedWhen varying electric currents are transmitted over long circuits theyare attenuated in a manner which is indicated by the formula if or thatis, at any distance :0 from the sou cc of current, its strength willhave decreased from unity to e'", or in that proportion: where e is thebase of the Naperian system of logarithms, a is the distance, in anyconvenient units of length, and p, which may be termeri the attenuationconstant, is equal In this formula, C is the electrostatic capacity, Rthe resistance, and L the inductance, all per unit length, and m isequal to 21: times the frequency of the current. When a current iscomposed of waves of different frequencies, these component waves willbe attenuated in difl'erent degrees, and the resulting current, orcombined wave, will be not only attenuated but distorted. This isnotably the case in telephonic transmission. When the inductance of acircuit, L, is practically zero, the abox e formula reduces to V ,ICLUR2 When, however, the inductance, L, is

made large com ared with the resistance, R,

the expression or p becomes which is independent of the fre uency, sothat currents made up of waves 0 different frequencies will have theircomponents attenuated in the same de rec and will not suffer distortion.And a so, by increasing L, the attenuation can be minimized.

The inductance of a circuit constructedv on my system can be calculatedby the formula tended primarily for submarine work, of a length of 2,000nautical miles. I take a. conductor of .164 square centimeters incross-sectional area, having a resistance of 2 ohms to :1 nautical mile,and a capacity of 0.3 microfarads per nautical mile; and a core of 0.5square centimeters in area, which will be 0.8 centimeters in diameter;the pitch of the helical conductor I make equal to 2 centimeters. Then,making allowance for the thickness of conductor and insulation, as wellas the compression of the insulation and other minor features, theaverage diameter of the helix is brought to one centimeter. On such aline the length of the conductor is increased in the ratio of 1.85 to 1,and the resistance of the conductor, therefore, equals 3.7 ohms pernautical mile; allowing thatthe capacity is increased in the safneproportion, it will be 0.555 microfarads per nautieel mile. Theattenuation constant will then be If"? "Tifi2'' and the attefflfatbntherefore will be:

Hi l

= groom; 72

, and this for a cable of 2,000 nautical miles; and this attenuation inmy construction is, furthermore, independent of the frequency.

As a partial basis of comparison to show the relative entireimpracticability of an ordinary cable, as compared with one of myconstruction, consider such an ordinary cable 2000 nautical miles inlength, with a resistance .of 2 ohms and a capacitywf 0.3 microfaradsper mile. he inductance of such a cable is extremely small, and t eformula for the attenuation constant is there fore:

CwR P 2 Substituting the above values, and assuming the frequency to be500,

' 0.3x27FY5tYl3ZT2 1 p= ,,/942=.031.

The attenuation for a 2000 mile cable will therefore be:

1 1 1 5,2 ado 3172666) 55 r.

ap roximately. Moreover, this attenuation wi l vary with the frequen y.4

I make the strands of the core of fine softiron wire. These wires may beinsulated from each other by a coating of their oxid, or they may have athin coating of insulating compound. In cases where it mi ht be foundadvantageous to have the core e ectromagnetically non-continuouslongitudinally,

the plumiity of strands in my efmezi' form afiord the opportunityof-stil preservin'g mechanical continuity by staggering the 1011118;

I do not wish to confine myself to the exact constructions or dimensionsof parts as herein specifically set forth, but What I- and increasingitscapacity in a lesser degree, substantially as described.

2. The method of wnn'teract'ing the capacity'of anelectric' cable, whichconsists in increasing the efl'ective inductance of the cable throughoutall portions of the length tl icreof, and increasing its resistance in alcsserdegr'ee'.

In testimony whereof, I have signed my -1 name to this specification, inthe presence of two subscribing witnesses, this 12th day of April, 1905.

JOHANNES H; GUNTZ; Witnesses:-

P. KENNEM,

F. Con-rm

